Augmented synthetic control report, single treatment

Overview

This repository provides code and sample data to estimate the effect of single state’s policy on birth outcomes using the augmented synthetic control method (ASCM) utilizing the augsynth package. This report displays select results and their corresponding diagnostic tables and plots.

The policy exposure in this example is Texas Senate Bill 8 (TX SB 8), a 6 week gestational ban on abortion that went into effect on September 1, 2021.

All results are generated using synthetic data and therefore are for educational purposes only.

Cohort definition

Inclusion criteria

All births and fetal deaths beginning January 1, 2014

Exclusion criteria

Singleton births and fetal deaths
Gestational age \(\geq\) 20 weeks
Removed Connecticut records due to undercounting of fetal deaths
Removed Virginia due to record quality (maternal morbidity outcomes only, not shown in this report)

Exposure definitions

Exposure 1: policy implemented by at least 6 weeks gestation

Pregnancies are exposed if, by the date the policy went into effect, the pregnancy was at least 6 weeks gestational age.

Pregnancies where the stillbirth or birth occurred before the policy went into effect are unexposed
Pregnancies that were under 6 weeks gestational age by the date the policy went into effect are removed from the analysis (i.e., only looking at the first cohort of pregnancies)

Due to the nature of preterm births, for this exposure definition observations on or before April 1, 2022 for this analysis need to be removed.

Exposure 2: policy implemented at any time during pregnancy

Pregnancies are considered exposed if the policy was in effect for any portion of the pregnancy.

Pregnancies where the stillbirth or birth occurred before the policy went into effect are unexposed
No additional pregnancies are removed

Due to other states receiving the treatment (i.e., causing unbalanced data) the post-treatment period ends at May 1, 2022.

Outcomes

Stillbirth rate
Preterm birth rate, conventional approach: live births are only included in the denominator
Preterm birth rate, “fetus-at-risk approach”: live births and stillbirths are included in the denominator

Time-varying confounders

State Medicaid expansion
State proportion of pregnancies where maternal age \(\geq\) 35 at the time of the stillbirth or birth

Results and ASCM diagnostics

Exposure 1: policy implemented by at least 6 weeks gestation

Stillbirth

Stillbirth ATT
Time	Estimate	Lower CI	Upper CI	p value
0	0.036	-0.170	0.242	0.824
1	0.154	-0.052	0.360	0.355
2	0.138	-0.068	0.344	0.351
3	-0.129	-0.335	0.077	0.408
4	-0.016	-0.222	0.190	0.933
5	-0.027	-0.233	0.179	0.847
6	-0.112	-0.318	0.094	0.509

Stillbirth observed and synthetic summary
		Observed				Synthetic
Period	Months	Mean	SE	Lower CI	Upper CI	Mean	SE	Lower CI	Upper CI
Post-Policy	7	0.515	0.035	0.429	0.60	0.508	0.023	0.452	0.565
Pre-Policy	92	0.527	0.016	0.495	0.56	0.527	0.007	0.514	0.541

Stillbirth RMSE
Average ATT	Pretreatment RMSE
0.006	0.138

Preterm birth, conventional approach

PTB ATT
Time	Estimate	Lower CI	Upper CI	p value
0	0.276	-0.359	0.912	0.492
1	0.128	-0.507	0.763	0.755
2	-0.181	-0.816	0.455	0.688
3	0.559	-0.076	1.194	0.081
4	0.218	-0.417	0.853	0.647
5	-0.104	-0.740	0.531	0.893
6	0.459	-0.177	1.094	0.241

PTB summary
Period	Time Points	Observed mean	Observed SE	Observed Lower CI	Observed Upper CI	Synthetic mean	Synthetic SE	Synthetic Lower CI	Synthetic Upper CI
Post-Policy	7	11.739	0.219	11.203	12.275	11.545	0.210	11.030	12.060
Pre-Policy	92	11.080	0.083	10.916	11.245	11.080	0.072	10.938	11.223

PTB RMSE
Average ATT	Pretreatment RMSE
0.194	0.296

Preterm birth, fetus-at-risk approach

PTB FAR ATT
Time	Estimate	Lower CI	Upper CI	p value
0	0.281	-0.355	0.916	0.416
1	0.142	-0.493	0.778	0.742
2	-0.179	-0.815	0.456	0.714
3	0.570	-0.065	1.206	0.088
4	0.215	-0.421	0.851	0.633
5	-0.121	-0.757	0.515	0.899
6	0.436	-0.200	1.072	0.230

PTB FAR summary
Period	Time Points	Observed mean	Observed SE	Observed Lower CI	Observed Upper CI	Synthetic mean	Synthetic SE	Synthetic Lower CI	Synthetic Upper CI
Post-Policy	7	11.703	0.217	11.173	12.234	11.511	0.204	11.013	12.010
Pre-Policy	92	11.033	0.083	10.868	11.197	11.033	0.072	10.891	11.175

PTB FAR RMSE
Average ATT	Pretreatment RMSE
0.192	0.295

Exposure 2: policy implemented at any point in pregnancy

Stillbirth

Stillbirth ATT
Time	Estimate	Lower CI	Upper CI	p value
0	-0.396	-0.797	0.000	0.054
1	0.227	-0.109	0.546	0.239
2	0.134	-0.217	0.470	0.412
3	0.298	-0.070	0.667	0.135
4	0.032	-0.353	0.433	0.818
5	0.058	-0.326	0.443	0.769
6	0.040	-0.345	0.441	0.849
7	0.007	-0.377	0.375	1.000

Stillbirth observed and synthetic summary
		Observed				Synthetic
Period	Months	Mean	SE	Lower CI	Upper CI	Mean	SE	Lower CI	Upper CI
Post-Policy	8	0.648	0.070	0.484	0.813	0.598	0.014	0.565	0.632
Pre-Policy	92	0.568	0.018	0.533	0.603	0.568	0.007	0.554	0.581

Stillbirth RMSE
Average ATT	Pretreatment RMSE
0.05	0.139

Preterm birth, conventional approach

PTB ATT
Time	Estimate	Lower CI	Upper CI	p value
0	0.277	-0.487	1.041	0.480
1	0.138	-0.626	0.902	0.747
2	-0.148	-0.913	0.616	0.801
3	0.577	-0.125	1.341	0.099
4	0.226	-0.538	0.990	0.652
5	-0.031	-0.795	0.733	0.987
6	0.772	0.000	1.536	0.069
7	0.263	-0.501	1.027	0.645

PTB observed and synthetic summary
		Observed				Synthetic
Period	Months	Mean	SE	Lower CI	Upper CI	Mean	SE	Lower CI	Upper CI
Post-Policy	8	12.101	0.144	11.762	12.441	11.842	0.089	11.632	12.052
Pre-Policy	92	11.080	0.083	10.916	11.245	11.080	0.072	10.937	11.223

PTB RMSE
Average ATT	Pretreatment RMSE
0.259	0.298

Preterm birth, fetus-at-risk approach

PTB FAR ATT
Time	Estimate	Lower CI	Upper CI	p value
0	0.279	-0.481	1.040	0.505
1	0.151	-0.610	0.881	0.737
2	-0.146	-0.906	0.615	0.765
3	0.585	-0.175	1.346	0.078
4	0.237	-0.524	0.998	0.633
5	-0.035	-0.796	0.725	0.982
6	0.755	-0.006	1.516	0.074
7	0.255	-0.506	1.015	0.637

PTB FAR observed and synthetic summary
		Observed				Synthetic
Period	Months	Mean	SE	Lower CI	Upper CI	Mean	SE	Lower CI	Upper CI
Post-Policy	8	12.055	0.143	11.717	12.394	11.795	0.088	11.586	12.004
Pre-Policy	92	11.033	0.083	10.868	11.197	11.033	0.072	10.890	11.175

PTB FAR RMSE
Average ATT	Pretreatment RMSE
0.26	0.297